Transcript EXCRETION Urinary system with some IGCSE questions http://biodeluna.wordpress.com/ Homeostasis. • Homeostasis is the general function that controls and keeps constant the conditions of our body. Excretion it is the.

EXCRETION
Urinary system
with some IGCSE questions
http://biodeluna.wordpress.com/
Homeostasis.
• Homeostasis is the general function that
controls and keeps constant the
conditions of our body.
Excretion
it is the removal from organisms of toxic
materials, the waste products of
metabolism (chemical reactions in cells
including respiration) and substances in
excess of requirements.
Substances include carbon dioxide, urea and salts
Urinary system anatomy
• Excretory systems regulate the chemical
composition of body fluids by removing
metabolic wastes and retaining the proper
amounts of water, salts, and nutrients.
Components of this system in vertebrates
include:
the kidneys, liver, lungs, and skin.
http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookEXCRET.html
Outline structure of a kidney
The kidney
renal cortex
renal pelvis
pyramids
renal medulla
ureter
Kidney function
Removal of urea and excess water and the
reabsorption of glucose and some salts,
so:
• Remove wastes.
• Regulate water levels
The nephron
X section to nephron
Nephron
Nephron function
• role of renal capsule - filtration from blood
of water, glucose, urea and salts
• role of tubule - reabsorption of
glucose,most of the water and some salts
back into the blood, leading to
concentration of urea in the urine as well
as loss of excess water and salts
How can our body keep the
percentage of water in our body
around 60/70%?
•
60 – 70 % of the weight of our body is
water (around 40 l of water).
•
If it is very hot and we sweat, we lose
some of our body water composition.
If we lose water, we can suffer
dangerous dehydration
We have to” save” water and we must
not lose more water through urine.
The urine will be more concentrated
(water is reabsorbed)
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If we drink a lot of water, we have an
extra supply of water (that we don’t
need).
Our urine will be more diluted (water
will not be reabsorbed in kidneys).
Urea
• Urea is formed in the liver from excess
amino acids most of the water and some
salts back
How toxic waste from cellular
respiration (catabolism) is excreted
• 1- Blood + waste come to
kidneys by renal artery.
• 2-Filtration of waste in the
nephron.
• 3-Reabsorption of some
useful products that could have
been filtered, to the capillaries
surrounding the nephron.
• 4-Waste is concentrating as
urine.
• 5-Urine goes to the
-collecting duct
- ureter
- bladder
- and goes out by urethra
Kidney stones (renal calculi)
• It is the term commonly used to refer to stones,
or calculi, in the urinary system. Stones form in
the kidneys and may be found anywhere in the
urinary system. They vary in size. Some stones
cause great pain while others cause very little.
The aim of treatment is to remove the stones,
prevent infection, and prevent recurrence. Both
nonsurgical and surgical treatments are used.
Kidney stones affect men more often than
women.
Kidney stones form when there is a decrease
in urine volume and/or an excess of
stone-forming substances in the urine.
http://thoughtsandstuff.posterous.com/uh-oh-kidney-stonesouch
Renal (kidney) failure
• It results when the kidneys are not able to regulate water
and chemicals in the body or remove waste products
from your blood. Acute renal failure (ARF) is the sudden
onset of kidney failure. This condition can be caused by
an accident that injures the kidneys, loss of a lot of
blood, or some drugs or poisons. ARF may lead to
permanent loss of kidney function. But if the kidneys are
not seriously damaged, they may recover. Chronic
kidney disease (CKD) is the gradual reduction of kidney
function that may lead to permanent kidney failure, or
end-stage renal disease (ESRD). You may go several
years without knowing you have CKD.
Dialysis
• Artificial maintenance
of glucose and
protein concentration
in blood and diffusion
of urea from blood to
dialysis fluid.
In case of chronic
renal failure…
What about a kidney
transplant?
http://lifeblood.anaemiaworld.com/en/chronic-kidney-disease/kidney-transplant.html
• Advantages: Dialysis takes a HUGE
amount of time, and your life revolves
around it. You also risk infection.
A kidney transplant is permanent
• Disadvantages: Obviously, the risks
associated with any surgery, risk of
rejection by your body, and you have to
take anti-rejection drugs your whole life.
http://answers.yahoo.com/question/index?qid=20090331122335AAJiPAb
IGCSE – syllabus question
discuss the advantages and disadvantages of kidney
transplants, compared with dialysis
http://sandrabrinkhoff.artspan.com/large-view/Medical%20Illustration/96153---7624/Mixed%20Media.html
Some
IGCSE
questions
Sandra Brinkhoff
http://blogs.laweekly.com/style_council/interior-decor/urinary-tract-wallpaper/
• Some concepts
taken from
IGCSE Biology
syllabus 2010
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http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookEXCRET.html
http://en.wikipedia.org/wiki/Excretory_system
http://kidney.niddk.nih.gov/kudiseases/pubs/Yoururinary/